Blue azo dye and process of making same.



UNITED STATES PATENT OFFICE.-

' THILO KROEBER, OF BASEL, SWITZERLAND, ASSIGNOR TO THE FIRM OF SOCIETY OF CHEMICAL INDUSTRYIN BASLE, OF BASEL, SWITZERLAND.

BLl JE AZb DYE AND PROCESS'OF MAKING SAME- I To all whom it may concern:

' Be it known thatI, THI o KROEB ER, chemist and doctor of philosophy, a subject of the Duke of Saxe-Altenb'urg, and a resident of Basel, Switzerland, have invented new and useful Improvements in the Manufacture of.

Monoazo Dyestuffs, of which the following is a full, clear, and complete specification.

The invention relates to the manufacture of new monoazo dyestuffs derived from l-amido- 2 acidyloxynaphthalenesulfonic acids and naphtholsulfonic acids, according to the general process described in anapplication for Letters Patent executed by me and Dr. Karl J agerspacher, SerialNo. 261,897,,dated'May 23, 1905. 1

These new monoazo dyestuffs dissolve in water and in concentrated sulfuric acid with blue colorations and dye unmolgdanted wool Bordeaux tints becoming blue on treatment with chromium compoundsas, for instance,

potassium bichromate.

The following example illustrates the manufacture of the new dyestuff: 23.9 kilos of 1-2-amidonaphth0l-4-sulf0nic acid are dissolved in two hundred liters of-water with aid of forty-nine kilos of soda-lye of Baum and acetylized'by means of eleven kilos of acetic anhydrid at a temperature below 0 centigrade, while good stirring is maintained. After a few minutes there are added to the solution, which should have neu-' tral or feebly alkaline reaction, seven kilos of solid sodium nitrate, and the whole is acidified at 0 centigrade by adding all at once thirty kilos of ordinary hydrochloric acid, whereupon the mass immediately solidifies without any evolution of gas to a yellow crystalline magma. This diazo compound is allowed to flow immediately into a solution of twenty four kilos of 1% 5 naphtholsulfonio acid, alkaline with soda. There is first formed a red-violet dyestufl, a part of which sepa- -rates. By long standing, more quickly on heating to v centigrade, a pure-blue dye stuff is obtained, which is precipitated by adding common salt. It dissolves in water and in concentrated sulfuric acid with blue colora-- tions and dyes wool in acid-baths Bordeaux tints, which become blue by subsequent treatment with chromium compounds, By replacing in 'this example 1-.5-naphtholsulfonic acid by the isomeric l- I-naphtholsulfonic acid the obtained dyestuff of analogous propertiesbe- Specification of Letters Patent.

Application filed M8122, 1905. Serial No. 261,558. (Specimens) t Patented Dec, 5, 1905.

v i comes more reddish blue by it Wool with chromium compounds.

, Instead, of the 1-2-amidonaphthol-I-sulfonic acid mentioned in the example, other sulfonic acids of 1-2-amidonaphtholas, for instance, l-2-amidonaphtholr6-sulfonic acid, 1 2-amidonaphthol 4: 6 disulfonic acid 1-2-amido naphthol-3-6-disulfonic acid may also be employed.

What I claim is 1 1. The process for the manufacture of monoazo dyestuffs by acidylizin'g sulfonic acids of l-Q-amidonaphthol in thehydroxyl group, then diazotizing the so=obtained amido-2 acidyloxynaphthalenesulfonic acid and combining the resulting diazo compound with naphtholsulfonic acids.

2. The process for the manufacture of mo-' noazo dyestuffs, which process consists in acetylizing sulfonic acids of 1-2-amidonaphthol in the hydroxyl group, then diazotizing the soobtained 1-amido-2-acetoxynaphthas treatment onlenesulfonic acids and combining the resulting diazo compounds with naphtholsulfonic acids.

3. The process for the manufacture of a monoazo dyestuff, which process consists in acetylizing. l-2-amidonaphthol-L-sulfonic acid stuif yields blue solutions in water and in concentrated sulfuric acid and dyes unmordanted wool in Bordeaux shades becoming blue on treatment with chromium compounds.

- In witness whereof I have hereunto signed my name, this 9th day of May, 1905, in the presence of two subscribing witnesses.

THILO KROEBER.

Witnesses:

ALBERT GRAETE, AMAND BITTER. 

